Problem
You would like to construct a $95 \%$ confidence interval to estimate the population mean PCB (Polychiorinated biphenyl) level in white croaker fish from the Sa Francisco Bay. The random sample we select has a mean of 640 parts per milfion and a standard deviation of 54 parts per million. (a) What is the best point estimate, based on the sample, to use for the population mean? Tparts per million
Solution
Step 1 ：The best point estimate for the population mean is \(\boxed{640}\) parts per million.
